The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present disclosure.
The extraction and processing of hydrocarbons, particularly crude oil and natural gas, is an essential process necessitated by the world's increasing demand for fossil fuels of various compositions. The limited supply of oil and natural gas means that it is necessary to undergo continuous exploration in order to identify new oil and gas reserves, which are often situated in deep subsea locations.
Offshore oil and gas production platforms are generally very large structures which possess the capability and equipment to produce oil and gas from wells drilled into the sea bed, and either process it or store it until it can be taken to the shore. The first oil platforms were built and operated towards the end of the 19th century, and were able to extract hydrocarbons from shallow offshore wells.
As technology has advanced and the demand for oil and natural gas has risen, oil platforms have been operated in increasingly deep waters, to the point at which it has started to become technically and commercially unfeasible to fix the platforms to the sea bed. The first floating production unit (FPU) was developed in 1975 when the Argyll field in the UK North Sea was developed using a converted semi-submersible drilling rig, known as the Transworld 58. Two years later, in 1977, the first FPU based on a converted tanker was installed on the Shell Castellon field, extracting hydrocarbons from waters over 100 m off the coast of Spain. The use of a tanker hull allowed for produced oil to be stored on board and subsequently offloaded to a separate trading tanker. These converted tanker units were christened floating production storage and offloading units, or FPSOs.
A proliferation in deep water exploration and drilling over the past few years has resulted in a large number of new discoveries, which will now require development solutions. Market forecasts suggest that there are many offshore oil and gas projects in the planning and study phases which will require floating production units over the next several years. A significant number of these discoveries are relatively small fields which will be economically marginal compared to larger fields, and reductions in scale and cost of existing technologies, such as FPSOs, has not been able to deliver a sufficiently cost effective solution to produce and exploit these smaller fields. It is therefore necessary for an entirely new technology to be developed.
The objective technical problem addressed by the present disclosure, then, is the development of a compact, not normally manned floating production unit to be used for smaller offshore developments where the use of one of the existing larger scale manned floating production unit technologies is not cost effective. The process of installation of the present disclosure, where separate sections of the floating production unit are installed at the offshore location, is far cheaper and simpler and the requirement for heavy and expensive construction vessels is removed, and the elimination of the need for the floating production unit to be continuously manned will ensure lower operating costs.